The invention relates generally to semiconductor devices, and more particularly, to a method for doping spherical-shaped semiconductors.
The doping process involves the controlled introduction of an impurity to a substrate, which produces subtle changes in the electrical resistivity of the substrate. Such characteristics are necessary for solid-state electronic semiconductor devices, such as a transistor or integrated circuit.
A current method to produce doped, spherical single crystal substrates involves doping the surface of a polycrystalline silicon granule, and then melting it to create a homogeneously doped crystal. Both the doping and the melting comprise two separate steps that are carried out in a furnace in sequence. A third step involves processing (i.e. partial melting/recrystallizing) the homogeneously doped crystal to produce a doped single crystal.
In U.S. Pat. Nos. 5,278,097, 5,955,776, and 5,223,452, methods and apparatuses for doping spherical-shaped semiconductors are disclosed. However, an improved method of doping the spherical shaped semiconductors, which is simpler and more economical, is desired.